TripleA is a clone of the popular board game "Axis & Allies", which is a turn based strategy wargame. TripleA also acts as a game engine allowing creation of custom games with similar mechanics to Axis and Allies. It supports online play, network play, play-by-email, and single player vs AI or hot-seat. It comes with 11 different maps and the option to download more from online repositories. Most games take place during World War II, though there are mods to play other conflicts like the Napoleonic wars, or Lord of the Rings.

The OHRRPGCE (RPG Construction Engine) is a tool
for making your own retro 2D RPG games, in a style
similar to RPGs like the older Final Fantasy games
for the NES, SNES, or GBA. It includes, as an
example game, Fenrir-Lunaris's pixel-art
masterpiece "Vikings of Midgard".

Arx Libertatis is a cross-platform, open source port of Arx Fatalis, a 2002 first-person role-playing game developed by Arkane Studios. Arx Fatalis features crafting, melee and ranged combat, and a unique casting system where the player draws runes in real time to effect the desired spell. The Arx Libertatis source code is based on the publicly released Arx Fatalis sources. This does however not include the game data, so you need to obtain a copy of the original Arx Fatalis or its demo.

QTads is a cross-platform multimedia interpreter for Tads (Text Adventure Development System) games. Both Tads versions in use today (Tads 2 and Tads 3) are supported. It should be easy to port to a range of platforms, including embedded devices. MIDI, Ogg Vorbis, MP3, and WAV sound formats are supported.

bonzayRTS is a framework for tile-based (isometric) RTS games. It provides the basic entities for an RTS game with implemented SDL and GRP components. As a proof-of-concept, a Starcraft clone is being implemented with it.

FrobTADS is a complete rewrite of the Unix
console-version of TADS ("Text Adventure
Development System"). It uses curses (or ncurses)
and provides an interpreter to play games
developed with TADS as well as the TADS 2 and 3
development tools. It adds support for a number of
relatively recent user interface features
including full support for text and background
colors, TADS 3 banner windows, and timed input.
It's also much more portable and more easily
maintainable, as it's built to modern Unix standards.

Castle Game Engine is a cross-platform 3D game engine written in Object Pascal. It includes a flexible system of 3D objects, with out-of-the-box levels, items, intelligent creatures, and more. Rendering and processing of 3D models in X3D, VRML, Collada, and other formats is implemented. Many graphic effects are available, including shadows, bump mapping, shaders, mirrors, and screen effects.

The Brick Engine is a fast and simple lo-fi gaming engine. The engine provides a comprehensive API, including dazzling visual features, song playback, and collision detection: everything you need to make games with quickness and ease. The engine provides a straightforward C API and has language bindings for Tcl and Pascal, with support for more languages on the way.